Unused MB (multicast broadcast) SFN (single frequency network) subframes can be found in actually used radio resources. The current specification does not support sharing of these subframes. Some schemes have been proposed to reuse these subframes. Some of these schemes propose monitoring all MBSFN subframes. However, such solution has a large power-consumption, while for a user equipment (UE), saving power is an important indicator. Some other schemes propose to send a signaling to indicate reuse of MBSFN subframes in a physical downlink control channel (PDCCH); however, this solution is complex to implement and meanwhile will affect the physical layer. At the same time, all of these schemes explicitly require re-writing the RAN1 protocol, such that they will affect the entire RAN1 architecture.
Therefore, it is desirable for a solution of reusing MBSFN subframes, which will not cause impact on the current protocol while achieving a balance between power saving and implementation complexity.